Balancing energy supply during photosynthesis – a theoretical perspective

Matuszyńska, Anna; Saadat, Nima P.; Ebenhöh, Oliver

doi:10.1111/ppl.12962

Cited by 40 publications

(44 citation statements)

References 42 publications

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“…For example, the rate of NADH generation by Gly oxidation in C 3 plants can exceed the capacity at which it can be oxidized in the cytochrome branch of the respiratory chain, and this triggers NADH oxidation via the uncoupled alternative respiratory chain (Igamberdiev et al, 1997). Various kinetic models have included aspects of this regulation in the chloroplast in order to predict the engagement of cyclic electron transport, nonphotochemical quenching, and other electron sinks such as the water-water cycle, malate valve, and nitrate reduction (Riznichenko et al, 2009;Zaks et al, 2012;Matuszy nska et al, 2016Matuszy nska et al, , 2019. But these models lack consideration of extrachloroplastic metabolism that, as our FBA modeling demonstrates, can have a major bearing on the overall energy balance of the system and hence the engagement of energy-balancing regulatory mechanisms.…”

Section: Limits Of the Current Approachmentioning

confidence: 99%

Leaf Energy Balance Requires Mitochondrial Respiration and Export of Chloroplast NADPH in the Light

2019

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Key aspects of leaf mitochondrial metabolism in the light remain unresolved. For example, there is debate about the relative importance of exporting reducing equivalents from mitochondria for the peroxisomal steps of photorespiration versus oxidation of NADH to generate ATP by oxidative phosphorylation. Here, we address this and explore energetic coupling between organelles in the light using a diel flux balance analysis model. The model included more than 600 reactions of central metabolism with full stoichiometric accounting of energy production and consumption. Different scenarios of energy availability (light intensity) and demand (source leaf versus a growing leaf) were considered, and the model was constrained by the nonlinear relationship between light and CO 2 assimilation rate. The analysis demonstrated that the chloroplast can theoretically generate sufficient ATP to satisfy the energy requirements of the rest of the cell in addition to its own. However, this requires unrealistic high light use efficiency and, in practice, the availability of chloroplast-derived ATP is limited by chloroplast energy dissipation systems, such as nonphotochemical quenching, and the capacity of the chloroplast ATP export shuttles. Given these limitations, substantial mitochondrial ATP synthesis is required to fulfill cytosolic ATP requirements, with only minimal, or zero, export of mitochondrial reducing equivalents. The analysis also revealed the importance of exporting reducing equivalents from chloroplasts to sustain photorespiration. Hence, the chloroplast malate valve and triose phosphate-3-phosphoglycerate shuttle are predicted to have important metabolic roles, in addition to their more commonly discussed contribution to the avoidance of photooxidative stress.

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Section: Limits Of the Current Approachmentioning

confidence: 99%

Leaf Energy Balance Requires Mitochondrial Respiration and Export of Chloroplast NADPH in the Light

2019

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“…The photosynthetic electron transport chain converts light into chemical energy, supplying ATP and NADPH to drive the carbon dioxide reduction and fixation processes [29]. ATP synthase F1 complex (CF1) epsilon subunit (atpC, spot 7) is involved in the energy supply needed for the carbon dioxide reduction and fixation processes.…”

Section: Exogenous H 2 S Alleviates Growth and Photosynthesis Inhibitmentioning

confidence: 99%

Comparative Proteomic Analysis Reveals the Regulatory Effects of H2S on Salt Tolerance of Mangrove Plant Kandelia obovata

Liu

Shen

Simón

et al. 2019

IJMS

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As a dominant mangrove species, Kandelia obovata is distributed in an intertidal marsh with an active H2S release. Whether H2S participates in the salt tolerance of mangrove plants is still ambiguous, although increasing evidence has demonstrated that H2S functions in plant responses to multiple abiotic stresses. In this study, NaHS was used as an H2S donor to investigate the regulatory mechanism of H2S on the salt tolerance of K. obovata seedlings by using a combined physiological and proteomic analysis. The results showed that the reduction in photosynthesis (Pn) caused by 400 mM of NaCl was recovered by the addition of NaHS (200 μM). Furthermore, the application of H2S enhanced the quantum efficiency of photosystem II (PSII) and the membrane lipid stability, implying that H2S is beneficial to the survival of K. obovata seedlings under high salinity. We further identified 37 differentially expressed proteins by proteomic approaches under salinity and NaHS treatments. Among them, the proteins that are related to photosynthesis, primary metabolism, stress response and hormone biosynthesis were primarily enriched. The physiological and proteomic results highlighted that exogenous H2S up-regulated photosynthesis and energy metabolism to help K. obovata to cope with high salinity. Specifically, H2S increased photosynthetic electron transfer, chlorophyll biosynthesis and carbon fixation in K. obovata leaves under salt stress. Furthermore, the abundances of other proteins related to the metabolic pathway, such as antioxidation (ascorbic acid peroxidase (APX), copper/zinc superoxide dismutase (CSD2), and pancreatic and duodenal homeobox 1 (PDX1)), protein synthesis (heat-shock protein (HSP), chaperonin family protein (Cpn) 20), nitrogen metabolism (glutamine synthetase 1 and 2 (GS2), GS1:1), glycolysis (phosphoglycerate kinase (PGK) and triosephosphate isomerase (TPI)), and the ascorbate–glutathione (AsA–GSH) cycle were increased by H2S under high salinity. These findings provide new insights into the roles of H2S in the adaptations of the K. obovata mangrove plant to high salinity environments.

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“…R. Soc. B 375: 20190448 parameters that are not easily accessible experimentally, and thus to draw general conclusions about regulatory principles [80][81][82]. In addition, two more promising concepts for pathway analysis that assesses inherent properties in biochemical reaction networks [83,84] rely on the related concepts of elementary flux modes [85,86] and extreme pathways [87][88][89][90].…”

Section: (F ) Pathway Reconstructionmentioning

confidence: 99%

From sequence to information

Popa

Oldenburg

Ebenhöh

2020

Phil. Trans. R. Soc. B

Self Cite

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Today massive amounts of sequenced metagenomic and metatranscriptomic data from different ecological niches and environmental locations are available. Scientific progress depends critically on methods that allow extracting useful information from the various types of sequence data. Here, we will first discuss types of information contained in the various flavours of biological sequence data, and how this information can be interpreted to increase our scientific knowledge and understanding. We argue that a mechanistic understanding of biological systems analysed from different perspectives is required to consistently interpret experimental observations, and that this understanding is greatly facilitated by the generation and analysis of dynamic mathematical models. We conclude that, in order to construct mathematical models and to test mechanistic hypotheses, time-series data are of critical importance. We review diverse techniques to analyse time-series data and discuss various approaches by which time-series of biological sequence data have been successfully used to derive and test mechanistic hypotheses. Analysing the bottlenecks of current strategies in the extraction of knowledge and understanding from data, we conclude that combined experimental and theoretical efforts should be implemented as early as possible during the planning phase of individual experiments and scientific research projects. This article is part of the theme issue ‘Integrative research perspectives on marine conservation’.

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Balancing energy supply during photosynthesis – a theoretical perspective

Cited by 40 publications

References 42 publications

Leaf Energy Balance Requires Mitochondrial Respiration and Export of Chloroplast NADPH in the Light

Leaf Energy Balance Requires Mitochondrial Respiration and Export of Chloroplast NADPH in the Light

Comparative Proteomic Analysis Reveals the Regulatory Effects of H2S on Salt Tolerance of Mangrove Plant Kandelia obovata

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